A candle left unattended is believed to be the cause of a flat fire on Vauxhall Bridge Road in Pimlico.
Eight fire engines and around 60 firefighters tackled the fire in a fourth floor flat. Fire crews contained the fire to the flat of origin.
Around 30 residents began to evacuate the block and were assisted by firefighters wearing breathing apparatus. One woman was assessed at the scene by London Ambulance Service crews.
A London Fire Brigade spokesperson said: “Candles are one of the most common causes of fire.
“It’s really important that you never leave a candle unattended and keep them away from anything else that can easily catch fire.”
The Brigade was called at 0142 and the fire was under control by 0330. Fire crews from Lambeth, Chelsea, Soho, Clapham and Brixton fire stations were at the scene.